Modular monitoring and protection system with distributed voting logic

ABSTRACT

A system for monitoring and protection machine systems includes multiple monitoring modules positioned proximate to points of interest in the machine system where dynamic operating conditions are monitored. The monitoring modules, which may communicate with one another via an open industrial data exchange protocol, include user-configurable voting logic for controlling or protecting the machine system based upon the monitored conditions. The logic of the modules is interdependent such that certain of the responses will or will not be taken unless combined conditions occur as defined by the voting logic of multiple modules.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of systems formonitoring and protection of mechanical systems. More particularly, theinvention relates to a technique for providing sophisticated andinterdependent voting logic in monitoring and protection systems so asto permit adaptation of a control or protection scheme to specificapplications.

In the field of industrial equipment monitoring and protection, a widerange of components and systems are known and presently in use.Depending upon the nature of the underlying mechanical system, themonitoring and protection components may generate various signalsrepresentative of dynamic conditions. The signal-generating componentsare typically sensors and transducers positioned on or otherwise closelyassociated with points of interest of the machine systems. The signalsare applied to monitoring circuits, typically somewhat remote from thepoints of interest, and are used to analyze the performance of themachine system. Machine systems thus instrumented may include rotarymachines, assembly lines, production equipment, material handlingequipment, power generation equipment, as well as many other types ofmachines of varying complexity.

A variety of unwanted conditions may develop in machine systems that canoccur rapidly, or develop over time or in certain situations, such asloading or due to wear or system degradation. Where unwanted conditionsappear, various types of response may be warranted. For example, theresponse of the monitoring and protection components to differentdynamic conditions may differ greatly depending upon the machine systemitself, its typical operating characteristics, the nature of the system,and the relative importance of the conditions that may develop. Suchresponses may range from taking no action, to reporting, to logging, toproviding alerts, and to energizing or de-energizing parts or all of themachine system.

By way of example, one type of condition that may be monitored in rotaryand other dynamic machine systems is vibration. Information indicativeof vibration may be collected by accelerometers on or adjacent to pointsof interest of a machine, and conveyed to monitoring or controlequipment. The information from the accelerometers is not typicallyuseful in its raw form, and must be processed, analyzed, and consideredin conjunction with other factors, such as operating speeds, todetermine the appropriate response to existing or developing conditions.

Responses to monitored signals and processed data, such as vibrationaldata, may differ due to a number of factors. Again, these may includethe normal operating characteristics of the machine system. Also,however, particular bands or ranges of speeds or frequencies may be ofparticular interest due to the relatively greater impact of systemresponse at such frequencies. Moreover, during certain operatingperiods, such as during startup or a change in speed or loading, thevarious ranges may be of greater or lesser interest in deciding upon anappropriate response.

Existing monitoring and protection systems, such as those used tomonitor vibrational data do not provide a desired degree of versatilityin configuration to accommodate such factors. In particular, wheredifferent monitors are positioned adjacent to different points ofinterest in a machine system, responses may typically be coordinated bya central monitoring or control system. The resulting reaction times maybe unacceptably long, the resulting system is somewhat less adaptablethan would be desirable. That is, where centralized control isimplemented, flexibility and adaptability of the system to a moredistributed, and generally more rapid, control by the individualmonitoring modules is sacrificed.

There is a need for a more flexible and distributed approach tomonitoring and protection systems. Moreover, there is a need for systemsthat can implement relatively sophisticated control or protection logicin a more distributed and interdependent fashion between variousmonitoring modules applied to a complex machine system.

SUMMARY OF THE INVENTION

The present invention provides a monitoring and protection techniquedesigned to respond to such needs. The technique may be applied in awide range of settings, but is particularly useful for controllingcomponents of relatively complex machines, such as material handlingequipment, rotary equipment, production equipment, and so forth. Themonitored parameters may also vary widely, although the technique isparticularly well suited to monitoring and controlling dynamic operatingconditions of machines. Similarly, the responses implemented may vary,although these will typically include the energization orde-energization of components, such as via relay circuits.

The technique makes use of voting logic that is distributed amongdifferent monitoring modules and/or relay circuits. The monitoringmodules are positioned proximate to points of interest in a machinesystem where dynamic operating conditions are monitored via sensors ortransducers coupled to the various monitoring modules. The modulespreferably communicate with one another via an open industrial dataexchange protocol. Voting logic is stored within each monitoring moduleand the logic of at least one device is based upon logic, or outputsignals resulting from logic of another module. The logic may be userconfigured to permit various combinations of conditions to exist beforedesired responses are taken.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages and features of the invention willbecome apparent upon reading the following detailed description and uponreference to the drawings in which:

FIG. 1 is a diagrammatical overview of a machine system employing amodule monitoring and protection system in accordance with aspects ofthe present technique;

FIG. 2 is an exemplary topology for modules and related equipment foruse in a machine system of the type shown in FIG. 1;

FIG. 3 is a diagrammatical representation of a series of associatedmodules in a group;

FIG. 4 is an exemplary physical configuration of modules within anenclosure, such as at a desired machine location;

FIG. 5 is a perspective view of an exemplary module implementation foraccepting a monitoring module on a standard interface that communicateswith similar interfaces and modules via the present technique;

FIG. 6 is a diagrammatical representation of exemplary functionalcomponents of a module for performing and monitoring and/or protectionfunctions;

FIG. 7A is a graphical representation of dynamic parameter data, such asvibrational data, indicating a manner in which various alarm settingsmay be implemented and utilized;

FIG. 7B is a graphical representation of a technique for multiplying orraising certain alarm settings, such as during startup or shutdown ofmonitored systems;

FIG. 8 is a diagrammatical representation of the interplay betweenprogram settings in a series of monitors and relay modules, such as formore complex voting logic schemes in accordance with aspects of thepresent technique; and

FIG. 9 is a flow chart illustrating an exemplary process for programmingor reprogramming configuration settings within a module in accordancewith aspects of the present technique.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Turning now to the drawings, and referring first to FIG. 1, adiagrammatical overview is illustrated of a monitoring and protectionsystem 10 applied to an exemplary machine system 12. The monitoring andprotection system 10 is particularly well-suited for detecting,monitoring, and controlling a wide range of dynamic operating parametersof machine systems. In particular, the system is well-suited to varioustypes of rotary equipment, although other applications may be envisagedfor certain aspects of the present technique. As used herein, the term“dynamic operating condition,” or the reference to dynamic conditions ingeneral, is intended to convey physical conditions or parameters of amachine system, as opposed, for example, to electrical conditions. Thedynamic conditions may include such characteristics as vibration,rotation, speed, temperature, pressure, and so forth.

The monitoring and protection system 10 is designed to permit selectivemonitoring of dynamic operating conditions and parameters at variouspoints along a machine system. In general, these points will correspondto locations at which such parameters can be sensed, and may beseparated, independent or quite distal from one another. In theimplementation illustrated in FIG. 1, for example, the mechanical system12 generally represents a power generation system in which a wide rangeof dynamic operating conditions are monitored on a continual basis forinformational, protection and control purposes. Accordingly, themonitoring and protection system 10 includes a series of sensors,detectors or transducers 14 mounted near or on various points of themachine system to detect the desired dynamic operating conditions.Communication lines 16 extend from the various sensors and transducersto monitoring assemblies 18.

The monitoring assemblies may be placed proximate to, adjacent to, orrelatively close to the various monitored locations or points, and neednot be grouped as in certain heretofore known systems. Certain of themonitoring assemblies, which will be described in greater detail below,may be linked via hosts 20. The hosts, or the monitoring assembliesdirectly, may be linked to central or remote monitoring stations 22 and24 both within a plant or installation, or remote from the plant orinstallation. Typically, the monitoring assemblies 18 will be mountedclosely adjacent to specific points or locations which are monitored,while hosts, if present, will be positioned near groups of monitors, oradjacent to a monitoring assembly. The central or remote monitoringstation is typically provided in a desired plant location, such as acontrol room, for programming, monitoring, protection and controlfunctions.

In the exemplary mechanical system 12 illustrated in FIG. 1, rotaryshafting 26 links a series of functional sections of the system,including a high pressure turbine section 28, a low pressure turbinesection 30, a generator 32 and an exciter 34. As will be appreciated bythose skilled in the art, the shafting and various components of thesystem are supported by a series of bearings 36. Other components mayclearly be included in the system, although the representation of FIG. 1has been intentionally simplified for explanatory purposes.

Throughout the present discussion it should be borne in mind that theturbine mechanical system of FIG. 1 is simply an example of oneapplication. The present technique may be applied in a wide range ofindustrial settings, including to material handling applications,production equipment, assembly stations and lines, just to name a few.Moreover, the various components of the mechanical system need not belinked by single shafting, but may be disparate and linked onlyfunctionally in the overall system design. In the case of a turbinesystem, however, the various sensors, transducers, monitors, and othercomponents of the system may form part of a turbine supervisoryinstrumentation system.

The various sensors and transducers 14 of the monitoring and protectionsystem 10 may produce a wide range of signals based upon the detecteddynamic operating conditions. Each generates one or more signals whichis applied to monitors within each monitoring assembly 18 via thecommunication lines 16. The various transducers may be active orpassive, and may receive power for operation via the communicationlines. By way of example, the sensors and transducers of theinstrumented turbine system of FIG. 1 may detect dynamic operatingconditions such as valve position and case expansion, as indicateddiagrammatically to the upper left in FIG. 1, eccentricity, bearingabsolute casing vibration, both in X and Y directions, differentialexpansion, speed of rotation, rotational phase, and so forth. As will benoted by those skilled in the art, various sensors and transducers maybe employed for these purposes, including linear variable differentialtransformers, non-contact pickups, rotary potentiometers,accelerometers, and so forth. Indeed, in a present implementation, theparticular configuration of monitors within the monitoring assembliesincludes a specially adapted vibration monitor designed to be coupled toa tachometer and to an accelerometer. Such accelerometers may detect,for example, signals indicative of shaft, casing or pedestal vibration,depending upon the application.

The monitoring assemblies 18 serve generally to receive, process, reportand act upon the signals supplied by the sensors and transducers. Forexample, specific monitors within the assemblies may process inputsignals to produce vibrational data which is used to analyze theperformance or operating conditions of the mechanical system. Wheredesired, and as described more fully below, specific processing of thistype may be implemented via the monitors of each or certain monitoringassemblies, and closed-loop protection of the equipment may be provided,such as to energize or de-energize the components or a single componentof the system. As will be appreciated by those skilled in the art,certain of the monitored dynamic operating conditions may beparticularly indicative of abnormal and unwanted conditions, such aswear, impending failure, unbalance, excessive loading, and so forth.Also as described more fully below, certain of the monitors within themonitoring assemblies may be designed to energize or de-energize aninternal or external relay or similar switch to permit rapid control andprotection functions. It should be noted that, as used herein, the term“relay” applies generally to a variety of switching devices which may becontrolled by the monitoring modules, such as conventionalelectromechanical devices, solid state devices, as well as otherswitching systems.

In addition to processing and analysis within the monitors of eachmonitoring assembly, each monitoring assembly may generally provideoutputs for external devices as indicated at reference numeral 38 inFIG. 1. The outputs may include electrical signals which can be appliedto dedicated components, such as motors, alarms, lights, valves, and soforth. These outputs are generated based upon the monitoring andanalysis functions performed by the monitoring modules and, dependingupon the programming of the various modules, with input from remotedevices such as the other monitoring assembly modules or a central orremote monitoring station.

As described more fully below, the monitors or monitoring modules of thepresent technique make use of an open industrial data exchange protocolfor the exchange of information both between monitoring modules withineach monitoring assembly, and between the modules of differentmonitoring assemblies, and may use the same protocol for the exchange ofdata with remote devices such as hosts and central or remote monitoringstations. As used herein, the term “open industrial data exchangeprotocol” generally refers to a non-proprietary and non-fee based schemefor formatting and transmitting data traffic between independentdevices. A variety of such protocols have been developed and arepresently available, including protocols designated generally in theindustrial field as DeviceNet, ControlNet, Profibus and Modbus. Certainof such protocols may be administered by industry associations or bodiesto ensure their open nature and to facilitate compliance with theprotocol standards, such as the Open DeviceNet Vendors Association. Ithas been found that the use of a standard open industrial data exchangeprotocol for some or all of the communications between the modules,between assemblies, and between remote devices and the modules andassemblies, greatly enhances the interchangeability and applicability ofthe present system in various settings. Moreover, as described morefully below, the use of the open industrial data exchange protocolpermits the individual monitoring modules to be easily interfaced in acompletely modular and independent fashion without the use of atraditional backplane architecture.

Due to the use of the open industrial data exchange protocol, themonitoring assemblies, and the various modules within the assemblies,may be linked to one another via standard network media 40, illustratedbetween the monitoring assemblies 18 and the host 20 in FIG. 1. Similarmedia may be routed both within each monitoring assembly, and betweenassemblies. While any suitable media may be employed for this purpose,for data exchange only, a two-conductor or shielded cabling system maybe employed. Where, as in the present system, data and power may beprovided at certain locations, a conventional network media such as afour-conductor cable may be applied for network media 40. In the presentembodiment, the media may include both power and data conductorsdisposed in a flat insulating jacket designed to interface theconductors with devices by conventional termination and by insulationdisplacement connectors. Further network media 42 serve to link themonitoring assemblies or hosts with remote monitoring equipment. Itshould be noted that the media 40 and 42 may be identical where desired.

Those skilled in the art will recognize that the topology afforded bythe present technique presents distinct advantages in terms of thephysical media employed to connect the various components of the system.For example, conventional sensor or transducer wiring may be routed tothe various monitoring assemblies, with internal wiring within themonitoring assemblies being greatly simplified by the use of an openindustrial data exchange protocol and by the interfacing of individualmodules as described below. Moreover, due to the de-centralized ordistributed nature of the monitoring modules and monitoring assembliesin the topology, individual monitoring modules and assemblies may beplaced local to specific points of interest in the machine system, withno need to route complex and bulky physical media to a central stationor bank for interfacing with a conventional backplane-based monitoringassembly.

The various centralized or remote monitoring stations 22 and 24 mayinclude any suitable equipment, such as general purpose orapplication-specific computers 44, monitors 46, interface devices 48,and output devices 50. Although simple computer systems are illustrateddiagrammatically in FIG. 1, those skilled in the art will recognize thatthe centralized or remote monitoring stations may include highly complexanalytical equipment, logging equipment, operator interface stations,control rooms, control centers, and so forth. As noted above, while atleast one such monitoring station will typically be provided at or nearthe application, other stations may be provided entirely remote from theapplication, such as for monitoring plants, lines, production equipment,offshore facilities, and the like from entirely remote access points.

FIG. 2 illustrates an exemplary topology for a monitoring and protectionsystem 10 in accordance with aspects of the present technique. In thetopology of FIG. 2, modular monitors are associated in groups 52, 54,56, 58 and 60. Each group may contain as few as a single monitor, and asmany associated monitors as necessary at a desired point of interest ofthe machine system. Again, the individual monitors, designated generallyby reference numeral 62 in FIG. 2, are designed to communicate databetween themselves in accordance with an open industrial data exchangeprotocol, and are individually mounted and interfaced without the use ofa conventional communications backplane. The monitoring module groupsmay further include one or more gateways configured to receive ormonitor signals from the monitoring modules and to convey correspondingsignals, in accordance with the same or a different data exchangeprotocol, to remote devices. For example, gateways 64 may afford dataexchange in accordance with different open industrial data exchangeprotocols, enabling the use of multiple such protocols within thesystem, such as two or more of the protocols mentioned above. Othergateways may provide for easily interfacing external devices, includingprogrammable logic controllers or digital control systems 66.

In the overall topology, then, certain of the monitoring devices ormodules may be in direct communication with a remote or centralmonitoring and control station, such as a PLC or DCS 66, as indicated bydata lines 68 in FIG. 2. Other communications may be provided to suchdevices as indicated at data lines 70, such as through branch lines 72interconnected with appropriate gateways within the monitoring groups.Similarly, gateways 64 may provide for communication in accordance withfurther exemplary protocols, such as Ethernet or Internet protocols.Appropriate communications lines 74 are provided in these cases, and maybe interfaced with the PLC or DCS 66 and with one or more hosts 20. Inthe case of Ethernet or Internet protocols, remote lines may be providedfor data exchange with devices both within a facility and quite remotefrom the facility, such as via the Internet.

As noted above, in addition to facilitating the truly modular nature ofthe present system without reliance upon a conventional backplanearchitecture, the use of an open industrial data exchange protocolfacilitates the exchange of data between monitoring groups orassemblies. Benefits of such topologies will readily appear to thoseskilled in the art. For example, the absence of a conventional backplanemay effectively reduce the cost and size of the overall system,particularly where few monitoring modules are employed at specificlocations of interest. Moreover, the overall system topology isinherently expandable and contractible to fit a particular application,with one or more monitoring modules being easily added to the system atdesignated locations of interest along the machine system. Moreover, asnoted above, the use of network media for communicating signals betweendisparate and separated monitoring groups rather than a centralrack-type monitoring station greatly reduces the cost and complexity ofinterconnections in the overall system, and specifically of wiringbetween the various sensors and a conventional central rack.

As mentioned above, in specific implementations, the monitoring modulesmay perform desired measurement and processing functions, and may alsoserve to energize or de-energize components of the machine system. FIG.3 illustrates diagrammatically several monitoring modules within amonitoring group or assembly 18 of the type illustrated in FIG. 1. Inthe illustrated example, the monitoring assembly 18 includes a series ofmonitoring modules 76, 78 and 80. Each of the modules in the illustratedembodiment receives input signals at lines 16 and includes acorresponding signal processing section 82, and a relay portion 84. Theprocessing section 82 includes circuitry for receiving, processing, andacting upon signals received from the various sensors and transducers.In a present implementation, for example, processing includes analysisof received signals for determination of vibrational data, such as via aFast Fourier Transform. As described more fully below, each monitor mayinclude specialized processors adapted for these functions, as well asmemory circuitry for storing configuration parameters in processingroutines.

Based upon such processing, output signals may be produced and providedat output 88 in a manner described above, such as for controllingexternal relays, alarms, lights, LEDs, and other devices. At leastcertain of the monitors in a present embodiment further include anintegrated relay 84 which may produce output signals in a similarmanner, such as for completing or interrupting a current carrying paththrough a load, such as a motor control device, starter, valve,indicator light, alarm, and so forth. It has been found that integrationof a relay directly in monitoring modules which can be much closer tothe actual monitored points of interest, affords extremely rapidresponse times. In particular, it has been found that conformity withindustry standards for protective devices, such as American PetroleumInstitute (API) standard 670 can be met easily through the presentmonitoring system design and topology.

As mentioned above, to avoid the need for a conventional backplane, themonitors and monitoring modules of the present system are designed toexchange data in accordance with an open industrial data exchangeprotocol. Indeed, this protocol is said to provide the “backbone” of thesystem, as opposed to the communication backplane of conventionalsystems. Accordingly, data links, represented generally by referencenumeral 90 in FIG. 3 are provided between the monitoring modules.Various physical configurations for such links may be envisaged.Conventional wiring may be provided, such as through terminated wires orinsulation displacement-type connectors. In a present embodiment,however, data links are provided between the modules by use ofinterconnecting terminal bases as described more fully below. Eachindividual module, then, is adapted for data exchange in accordance withthe adopted protocol. The monitoring assembly 18 may further includepower supply 92, typically providing constant voltage DC power,typically in the order of 24 volts. Alternatively, the media providingnetwork links to the individual monitoring assemblies may provide forpower needs as well, such as through a power and data cable. Powersupply lines 94 are routed to the individual monitoring modules, such asthrough the interfaced terminal bases.

To permit routing of signals to external devices, one or morecommunications circuits 96 may be provided within the monitoringassembly. In the foregoing arrangements, for example, the communicationscircuit 96 included a gateway which may be used to communicate data toremote locations via the same open industrial data exchange protocolused between the modules, or via a different protocol. It should benoted that a wide range of other devices may be provided in theassembly. The monitors themselves may be specifically adapted forcertain functions, including vibration monitoring, speed monitoring,temperature monitoring, pressure monitoring, and so forth. Other devicesmay then include relay modules comprising one or more individual relaycircuits controlled by the monitors, and probe drivers such asillustrated at reference numeral 100 in FIG. 3. Such probe drivers willtypically provide power to probes or sensors 102 which are linked to theindividual monitors.

As mentioned above, the present monitoring system design and topologyfacilitate the free association of independent and modular monitors atpoints of interest around a machine system to monitor and controldynamic operating conditions. FIG. 4 illustrates a typical installationfor one such group or assembly of devices at a machine location. In apresent embodiment, the various monitors and associated devices areadapted for mounting in an enclosure 104, such as a conventional NEMAenclosure. A panel 106 serves for mechanical mounting of the variousdevices, such as through the use of DIN rails 108.

In the embodiment illustrated in FIG. 4, the components of assembly 18include a monitoring module 110, such as a vibration monitor, one ormore terminal bases 112, a gateway 114, a signal conditioning module 116and a relay module 118. A power supply 92 is coupled to the relay moduleand to the monitoring module and gateway via appropriate powerconductors. Each module appropriately conditions and regulates powerreceived from the power supply. The terminal base 112, which may includea plurality of terminal bases, such as individual bases for themonitoring module and relay module, serves to receive terminatedconductors for routing signals to and from the modules, such as to andfrom sensors, transducers, and controlled devices, such as relays,lights, alarms, and so forth. The assembly at each point of interest inthe machine system may therefore be expanded or contracted by theaddition of other monitoring, relay, or other modules both along asingle line or group interconnected via terminal bases, or by subsequentgroups interconnected with the modules at the location via conventionalnetwork media. The gateway and signal conditioning circuitry, then,serve to interconnect the various modules of an assembly or group withother modules of different assemblies or groups, or directly with acentral or remote monitoring station or host.

FIG. 5 illustrates a simplified perspective view of an actual monitoringmodule 76 and its terminal base. In the illustration of FIG. 5, theterminal base 120 serves to mechanically mount the module on a supportstructure, such as a DIN rail. Terminals 122 are provided forterminating conductors, such as data and power conductors used totransmit signals to and from the monitoring module. The terminals may beprovided in tiers 124 to facilitate the use of a substantial number ofterminations, 52 such terminations being provided for each terminal basein the present embodiment. An interface 126 is provided in the terminalbase for receiving a monitoring module 110. The interface 126 includesconnections for the various power and signal lines needed for themonitoring module, with the monitoring module including a similarelectrical interface along a bottom side thereof. The monitoring moduleinterface 128 thus simply plugs into the terminal base for completion ofall necessary connections. For interfacing the various monitoring, relayand other modules of a group or assembly, then, a terminal baseinterface 130 is provided. In the illustrative example of FIG. 5, theinterface 130 is extendable and retractable from the side surface of theterminal base, and, when extended, plugs into a conforming receptaclewithin an opposite side of a similar terminal base. Necessaryconnections for data exchange in accordance with the open industrialdata exchange protocol are then provided between the interface modulesvia the respective terminal bases.

As noted above, the individual monitoring modules include a circuitrydesigned to permit them to receive signals from sensors and transducers,and to process the signals and act upon the signals in accordance withpredetermined routines. FIG. 6 illustrates an exemplary configuration offunctional circuitry within a monitoring module in accordance with thepresent technique. As illustrated in FIG. 6, the monitoring moduleprocessing circuitry 82 includes a CPU 132 designed to carry out datamanagement functions, to coordinate the exchange of data, and to controlcertain processing functions. An analog-to-digital converter 134receives input signals as indicated at reference numeral 16, convertsthe input signals to digital signals and applies these signals to theCPU 132 or DPS 140. In a present embodiment, a 24 bit, 96 ksample/secondconverter provides extremely high resolution for the calculations madewithin the monitoring modules, although other sampling rates may beemployed. Similarly, a digital-to-analog converter 136 receives digitalsignals from the CPU 132 and provides output signals as indicated atreference numeral 88, such as for monitoring, analysis or recordingsystems. A memory circuit 138 stores configuration parameters and codes,as well as routines implemented by the CPU 132. Such routines mayinclude analysis of received signals, such as to determine vibrationaldata, including vibrational profiles as described more fully below. Theroutines may also include code for analyzing and comparing data topreset alarm limits or advisory limits. Moreover, the processing codestored within memory circuit 138 may permit comparison of varioussignals or value levels, flags, alarms and alerts, and similarparameters within a single monitor or with signals received from othermonitors or remote monitoring and control equipment, such as to definevoting logic for energization or de-energization of devices within thesystem.

It should be noted that a wide variety of configuration parameters maybe stored within each monitoring module. For example, sensor ortransducer parameters may include the transducer type, its sensitivity,units of measure, low and high fault settings, DC bias time constants,and so forth. In vibration monitoring modules, parameter settings mayinclude such settings as channel name (for each of the multiple channelsprovided), output data units, high pass filter settings, full scalesettings, sampling mode settings (e.g. synchronous or asynchronous), andso forth. Overall measurement parameters may also be set, such as forRMS calculations, peak calculations, peak-to-peak calculations, overalltime constant calculations, damping factor calculations, as well as arange of spectrum and time waveform parameters. The latter may includevalues such as maximum frequency, number of lines or bins in spectrummeasurements, period of waveforms, number of samples in waveformmeasurements, and window type (e.g. Hanning, rectangular, Hamming, flattop, and Kaiser Bessel). Band measurement parameters may also be set,such as RSS and peak signal detection settings, minimum and maximumfrequencies in bands, and so forth. Similarly, various settings may beprovided for speed or tachometer settings, such as for averaging, pulsesper revolution, trigger mode, and so forth.

In addition to the foregoing circuitry, certain of the monitors mayinclude a dedicated digital signal processor 140 as illustrated in FIG.6. In a present embodiment, for example, a dedicated digital signalprocessor is provided for carrying out certain analysis functions, andcompliments the CPU 132 in the signal processing provided in themonitoring module. In this present embodiment, vibrational data isderived from signals received by the monitoring module. Theanalog-to-digital converter 134 receives conditioned signals and appliesthese signals to the digital signal processor 140 either directly, as ina present embodiment, or indirectly such as via the CPU. Dedicatedprocessing can be performed on the signals, such as by application ofanalysis routines which may include a Fast Fourier Transform toestablish a vibrational profile over a range of speeds or frequencies ofinterest.

In a present embodiment, the CPU 132 performs functions such as controlof communications, including control of data traffic over a bus, serialcommunications, such as for configuration of the monitoring module andmemory circuitry, controls utilization of memory, and processes datafrom the digital signal processor 140. The CPU may also control suchfunctions as powering up and powering down devices, and control of arelay circuit, or other internal or external device. It has been foundthat, where provided, the digital signal processor 140 in conjunctionwith the processing capabilities of the CPU 132 can greatly enhance theperformance of the monitoring module both in terms of the computationsthat can be performed, and the rapidity with which such computations canbe performed. As will be appreciated by those skilled in the art, suchgains in processing capabilities can greatly enhance the responsivenessof the module to rapid changes in dynamic operating conditions.

Other circuitry which may be provided within the monitoring modulesincludes an internal relay 142 illustrated diagrammatically in FIG. 6.While such circuitry may also be complimented by external circuitry,such as individual relay modules as discussed above, the provision of aninternal relay circuit allows the monitoring module to perform extremelyrapid, locally closed-loop protective functions. Code stored withinmemory circuit 138 and executed by the CPU 132 may include localcomparisons of processed data, such as vibrational data, speed data,temperature data, pressure data, and so forth, to pre-set oroperator-configurable limits or ranges. Where such a limit is reached,extremely rapid response may be provided by the integrated relaycircuitry, the state of which can be quickly altered by the CPU 132.

The CPU 132 may also implement code which causes a change in the stateof the relay circuitry in response to signals received from remotesources such as other modules and central processing circuits.Effectively, then, the monitoring modules may implement protection orcontrol loops at several levels. Firstly, at a local level, the CPU mayalter the operating state of the relay circuit extremely rapidly due todetected changes in operating conditions and by comparison with desiredlevels or ranges. In a broader, more remote control loop, input signalsmay be processed and analyzed at least partially remotely, with commandsfor operation of the relay circuitry being transmitted from the remotelocation and simply implemented by the CPU or implemented by the CPU inconjunction with locally-produced analytical data.

Communications circuitry, such as control area network circuitry 144 ispreferably included in each monitoring module to permit the formatting,transmission, and reception of data in accordance with the desiredprotocols. As noted above, the present monitoring modules preferablycommunicate with other modules and with external circuitry via an openindustrial data exchange protocol.

As mentioned above, a present implementation of the techniques andmonitoring module designs discussed herein accommodates analysis ofvibrational data. Such vibrational data may be a key component inmechanical system monitoring, control and protection. In a presentimplementation, vibrational profiles are generated in dedicatedvibration monitors based upon multiple channels of signal acquisition,from accelerometers and tachometers. The circuitry within the vibrationmonitors performs any suitable analysis to generate vibrational data,which may be presented as a vibration profile. Alarm or alert ranges,limits, levels, and the like may be established and combined with thevibrational data for monitoring, protection and control functions bothwithin the monitoring module and in conjunction with other monitoringmodules and control devices.

FIG. 7A represents an exemplary vibrational profile as well as certainvibration bands and alarm levels which may be utilized in this way. Inthe graphical illustration of FIG. 7A, referred to generally byreference numeral 146, the magnitude of vibration, as indicated by axis148 is displayed at various frequencies along axis 150. The frequenciesmay be divided into desired bands as indicated at reference numeral 152,such as by reference to actual operating frequencies of the equipment.That is, bands may be established for analysis purposes which aredivided at any convenient point over a range of frequencies of interest(including overlapping or spaced apart bands. The actual vibrationprofile 154 extends across the bands 152 and will typically exhibit arange of magnitudes depending upon the nature and characteristics of themachine system. As will be appreciated by those skilled in the art, forexample, a typical rotating machine system will exhibit certain naturalfrequencies which result in elevated magnitudes of vibration reachingpeaks as indicated generally at reference numeral 156 in FIG. 7A.

Heretofore known devices for analyzing machine vibration typicallyprovided an extremely limited ability to compare vibrational data withlimits defining unacceptable or undesirable conditions. In the presenttechnique, a large number of alarm limits may be set by a user throughconfigurable parameters stored within memory circuitry 138 describedabove with reference to FIG. 6. FIG. 7A illustrates a number of suchalarm limits indicated generally by reference numerals 158.

The alarm limits illustrated in FIG. 7A have several interesting andparticularly useful characteristics. Firstly, different alarm levels maybe set for different frequency bands, the limits of which may also beset, so as to allow for the specific tailoring of the monitoring andprotection functions to individual systems based upon their typical ordesired frequency response. Moreover, multiple alarm levels may be setby an operator for each frequency band and for the multiple frequencybands. Accordingly, the alarm levels may be configured so to defineranges such as minimum and maximum vibration levels. The configurationsalso permit the alarm levels to be used in various manners. By way ofexample, attaining certain alarm levels may result in reporting only,while attaining more elevated alarm levels may result in sounding ordisplaying an alarm, or in energization or de-energization of a relaycircuit so as to start or stop a piece of machinery. The rapid analysisof vibrational data in this manner, for example, may be used to start orstop electric motors, switch valves, illuminate lights, sound audiblealarms, and so forth.

FIG. 7B illustrates an additional feature of the alarms and theirutilization in the present technique. In particular, multipliers for oneor all of the alarms may be utilized to avoid false alarms for othererroneous feedback during periods of operation, such as startup orshutdown. In the illustration of FIG. 7B, for example, along a time axis151, a vibration trace, as indicated generally by trace 154, varies withthe magnitude of vibration, as indicated at axis 149. The actualoperating speed of the system is also represented along vertical axis153. Accordingly, in addition to the vibration trace 154, an operatingspeed trace 155 is illustrated. Within the time of the axis illustratedin FIG. 7B, therefore, the machine system, or a rotary portion of themachine system being monitored is brought up to speed. As will beappreciated by those skilled in the art, machine systems will typicallyexhibit one or more operating speeds at which vibration levels aresignificantly elevated. Thus, in the illustration of FIG. 7B, a largepeak develops as the machine system is brought up to speed (orconversely, as it is shut down).

As mentioned above, a number of alarm levels can be configured in thevibration monitor implementation of the present technique. Two suchalarm levels 157 are illustrated in FIG. 7B. The alarm multiplier of thepresent technique permits these levels to be increased during certainperiods of operation, typically during startup and shutdown, so as toavoid false alarms. In the graphical illustration of FIG. 7B, during aperiod from t₁ to t₂ spanning a range of speeds from RPM1 to RPM2, themultiplier is implemented to raise the alarm levels to levels 159. Thus,the peak that occurs within this speed range will not trigger an alarm.Such multipliers may be implemented to avoid such false alarms, eitheron a speed basis or on a time basis with the steady state alarm levelsconfigured in the monitors being returned following either the presettime or as the system rises above the speed. Other schemes of multiplierimplementation may, of course, be envisaged. The use of multipliers,therefore, allows the present system to conform to industry standardspecifications, such as API 670, paragraph 5.4.2.5 and Appendix I.

As already mentioned, a number of alarms and alerts may be configured ina present implementation of a vibration monitor incorporating aspects ofthe present technique. For example, in a current implementation twochannels are available in the vibration monitoring module, with 8 alarmsettings being available per channel. The number and a name designationof each alarm may be set, along with parameters for enabling ordisabling of each alarm. Conditions for response to the alarm settingsmay include “greater than,” “less than,” “inside range,” “outsiderange,” and various threshold settings for certain of these. Hysteresissettings may also be provided to prevent false alarms or to preventclearing of an alarm. Similarly, threshold multipliers and startupperiods may be set to prevent false alarms during periods of startup ortransition of machinery through certain resonant frequencies.

As noted above, the code stored and executed within each monitoringmodule may be combined with that of other modules or with remote controlequipment to create a voting logic structure which is extremely flexibleand configurable. FIG. 8 illustrates generally an exemplary topology orhierarchy which may be established by virtue of this modularity andconfigurability. The logic scheme, indicated generally by referencenumeral 160 may be thus distributed among devices, such as monitors 162and integrated or physically separate relay circuits 164. The monitors,relay circuits and any other devices which contribute to such votinglogic may be coupled through a network media 40 or 42 as describedabove. Configuration code within each monitoring module may then beimplemented including programmably by a user, to account for analyzeddata produced by the individual module, as well as data or signals fromother modules.

In a present implementation, certain conditions may be programmed withineach module as indicated generally at reference numeral 166. Theseconditions may include, by way of example, actual parameter levels orvalues, conditions such as whether an alarm or alert limit has beenexceeded, the particular state of a device, sensor, transducer, or otherinput, and so forth. These conditions alone may suffice for commandingthe change of state of an integrated or external relay circuit. However,the conditions may also be combined with other conditions monitored byother modules so as to define combinatorial logic and a voting logicstructure stored either within the individual modules or, as indicatedin FIG. 8, within the relay circuits. In the example of FIG. 8, therelay logic 168 may combine signals from two or more monitoring modules,such as to require a specific signal from more than one monitoringmodule, from one monitoring module but not another monitoring module, ormultiple types of signals, such as surge alerts, before effecting achange of state. In general, such combinatorial logic may be based uponBoolean logic conditions which are programmed either within themonitoring modules or within the relay circuits. Owing to the highdegree of modularity of the present system and its topology based uponthe open industrial data exchange protocol, such voting logic is easilyimplemented and configurable both as a system is initially installed andas a system is altered (i.e. expanded or contracted).

By way of specific example, in a present implementation, each monitoringmodule designed to allow for control of a relay may store variousconfiguration parameters for identifying and controlling the device.These may include a name and number of the relay, an enable and disableselection, and a latching setting (i.e. whether the relay stays in thealarm state when the signal causing the alarm has ended). Other settingsmay include “failsafe” operation settings and activation delay settings.The voting logic settings within each monitoring module may be basedupon Boolean-type logic, such as “Alarm A or Alarm B,” “Alarm A andAlarm B,” or “Alarm A only.” Based upon such conditions, multipleactivation selections are possible to define the conditions that willcause the relay to activate, such as “normal,” “alert,” “danger,”“disarm,” “transducer fault,” “module fault,” and “tachometer fault.”

As noted above, configuration code, including operating parameters,user-configurable parameters and values, alarm limits, alert limits, andthe like, may be stored within each monitoring module for processing,monitoring, protection and control functions. In a present embodiment,such code may be stored in other devices as well to permitreconfiguration of individual monitors, in the event the monitoringmodules are damaged, repaired, replaced. A present technique permitsautomatic device replacement and reconfiguration by storing the pre-setparameters for individual modules in a master module, with theindividual module taking the role of a slave. It should be understoodthat in the present context the designation of master and slave do notnecessarily reflect the control functions executed by or controlhierarchy established between the individual components. Rather, for thereconfiguration purposes, the designation indicates only that the masterstores the configuration parameters and can restore the configurationparameters in a slave when necessary.

FIG. 9 generally represents certain steps in logic for implementing suchautomatic device replacement and reconfiguration. The logic, designatedgenerally by reference numeral 170, begins after individual monitoringmodules have been placed in service. The monitoring modules communicateamong themselves in accordance with the open industrial data exchangeprotocol as described above. One of the modules, or another device, isdesignated as a master in a group, while other devices are designated asslaves. In a present embodiment, where a gateway is present in amonitoring group, the gateway will typically be employed as the master,with the monitoring modules themselves taking on the roles of slaves inthe reconfiguration scheme. Certain monitoring modules may, where nosuch gateway is present, or where desired, take on the role of mastersin this process.

In the summary of FIG. 9, the logic 170 begins at step 172 where aconfiguration file is loaded to a master, or at step 174 where themaster receives the configuration file from a slave. In either case, theconfiguration parameters may include pre-set parameter values, as wellas user-configurable values. Such user-configurable values may varygreatly depending upon the nature of the monitoring module and thefunctions it is to carry out in the system. In general, however, oncethe configuration file has been transmitted to the master it is storedin the master's memory circuitry as indicated by reference numeral 176.

In present embodiments, the configuration parameters of the files mayinclude specific parameters needed for the processing, protection,control and reporting functions executed by the monitoring module. Byway of example, the configuration parameters may include transducersettings, processor settings, alarms, comparison limits, ranges, and soforth. The entire file, as indicated generally by reference numeral 178in FIG. 9, is then stored both in the slave and in the master in aredundant fashion.

Once so configured, the system is allowed to operate in its normalfashion. During such operation, the master periodically either polls theslave or determines by some other means that the slave is operationaland responsive. Many techniques exist in the art for such monitoring ofoperational state. Once a slave has been determined to be unresponsive,as indicated at decision block 180 of FIG. 9, its address is detected bythe master as indicated at reference numeral 182. Within the overallsystem architecture, the various slaves and masters may be independentlyand specifically addressed in accordance with the open industrial dataexchange protocol. The address detected at step 182 permits the masterto correlate which device has become unresponsive with a specificconfiguration file stored in its memory. In the event the specificmonitoring module or slave is replaced, the slave will receive a newaddress, such as assigned by the master, which may be a specific addressin a sequence of available addresses. When a new or replacement modulecomes online, then, the master will determine whether the new module isa new slave, as indicated at reference numeral 184, based upon theaddress reported by the slave.

In the event of replacement, resetting, repowering, or any other eventwhich would cause the loss of configuration data in a slave, the mastermay replace the configuration file once the new slave has been detectedat step 184 of FIG. 9. In a present embodiment, the replacement isperformed by assigning a new or replacement address to the slave inplace of a default address as indicated at step 186, and by loading theconfiguration file stored within the master into the replacement addressas indicated at step 188.

In actual implementation, when a new or replacement module, or the samemodule following servicing, is replaced in the system, the replacementmodule comes online at the default address. The master module changesthe address of the replacement module from the default address to theaddress of the missing slave, that is, to the address detected for theunresponsive (e.g. removed) module. The master module then downloads theconfiguration corresponding to this address into the replacement module.Alternatively, the replacement module may be preprogrammed with theaddress of the missing module. In such situations, when the replacementmodule comes online at the missing module address, the configurationparameters are similarly downloaded by the master module. Thus, allnecessary configuration parameters, including specific alarm limits,voting logic functionality, and so forth, are restored to the monitoringmodule of interest.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown in the drawingsand have been described in detail herein by way of example only.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

What is claimed is:
 1. A system for monitoring and protection a machine,the system comprising: a first sensor for detecting a dynamic operatingparameter of the machine at a first location of interest and forgenerating a first signal representative thereof; a first monitorcoupled to the first sensor for receiving and processing the firstsignal, the first monitor including a memory for storing voting logicbased upon the received signal; a second sensor for detecting a dynamicoperating parameter of the machine at a second location of interest andfor generating a second signal representative thereof; a second monitorcoupled to the second sensor and to the first monitor, the secondmonitor receiving and processing the second signal and including amemory for storing voting logic based upon the received signal, thesecond monitor being configured to control an operative state of a relaybased upon a combination of the voting logic of the first monitor andthe voting logic of the second monitor.
 2. The system of claim 1,wherein the first monitor is configured to provide an output signal tothe second monitor based upon the voting logic of the first monitor, andwherein the second monitor is configured to utilize the output signal ofthe first monitor in the voting logic of the second monitor.
 3. Thesystem of claim 1, wherein the relay controlled by the second monitor isintegrated into the second monitor.
 4. The system of claim 1, whereinthe relay controlled by the second monitor is incorporated into a relaymodule local to the second monitor.
 5. The system of claim 1, furthercomprising a third sensor and a third monitor coupled to the thirdsensor and to the second monitor, the third monitor including votinglogic, and wherein the second monitor controls the relay based upon thevoting logic of the first, second and third monitors.
 6. The system ofclaim 1, wherein the voting logic of the first and second monitors is atleast partially based upon alarm settings within the respective monitor.7. The system of claim 6, wherein the alarm settings are userconfigurable.
 8. The system of claim 6, wherein at least one of thefirst and second monitors is configured to derive vibrational data fromthe received signal, and wherein at least one of the alarm settings isbased upon a vibration level as defined by the vibrational data.
 9. Thesystem o f claim 1, wherein the first and second monitors are configuredto exchange data in accordance with an open industrial data exchangeprotocol.
 10. The system of claim 1, wherein the voting logic of thefirst or the second monitor logically ANDs conditions indicated by therespective received signals.
 11. A system for monitoring and protectiona machine, the system comprising: a plurality of sensors for detecting adynamic operating parameter of the machine at a different location ofinterest and for generating a signals representative thereof; and aplurality of monitors, each monitor coupled to at least one sensor forreceiving and processing the generated signals; wherein each monitorincludes a memory device for storing distributed voting logic based uponthe received signals; and wherein at least one of the monitors isconfigured to control an operative state of a relay based upon acombination of the distributed voting logic of the plurality ofmonitors; and wherein the monitors are configured to exchange data inaccordance with an open industrial data exchange protocol.
 12. Thesystem of claim 11, wherein at least one of the monitors is configuredto derive vibrational data from the received signals, and wherein thevoting logic thereof is at least partially based upon the vibrationaldata.
 13. The system of claim 12, wherein the voting logic of themonitors is at least partially based upon alarm settings within therespective monitor.
 14. The system of claim 13, wherein at least one ofthe alarm settings is based upon a vibration level as defined by thevibrational data.
 15. The system of claim 13, wherein the alarm settingsare user configurable.
 16. The system of claim 11, wherein the votinglogic of the monitors logically ANDs conditions indicated by therespective received signals.
 17. The system of claim 11, wherein therelay controlled by the respective monitor is integrated therein. 18.The system of claim 11, wherein the relay controlled by the respectivemonitor is incorporated into a relay module local thereto.
 19. A systemfor monitoring and protection a machine, the system comprising: aplurality of sensors for detecting a dynamic operating parameter of themachine at a different location of interest and for generating a signalsrepresentative thereof; and a plurality of monitors, each monitorcoupled to at least one sensor for receiving and processing thegenerated signals; wherein each monitor includes a memory device forstoring distributed voting logic based upon the received signals; andwherein at least one of the monitors is configured to control anoperative state of a relay based upon a combination of the distributedvoting logic of the plurality of monitors; and wherein at least one ofthe monitors is configured to derive vibrational data from the receivedsignals, and wherein the voting logic thereof is at least partiallybased upon the vibrational data.
 20. The system of claim 19, wherein thevoting logic of the monitors is at least partially based upon alarmsettings within the respective monitor.
 21. The system of claim 20,wherein at least one of the alarm settings is based upon a vibrationlevel as defined by the vibrational data.
 22. The system of claim 20,wherein the alarm settings are user configurable.
 23. The system ofclaim 19, wherein the monitors are configured to exchange data inaccordance with an open industrial data exchange protocol.
 24. Thesystem of claim 19, wherein the voting logic of the monitors logicallyANDs conditions indicated by the respective received signals.
 25. Thesystem of claim 19, wherein the relay controlled by the respectivemonitor is integrated therein.
 26. The system of claim 19, wherein therelay controlled by the respective monitor is incorporated into a relaymodule local thereto.
 27. A system for monitoring and protection amachine, the system comprising: a plurality of sensors for detecting adynamic operating parameter of the machine at a different location ofinterest and for generating a signals representative thereof; and aplurality of monitors, each monitor coupled to at least one sensor forreceiving and processing the generated signals; wherein each monitorincludes a memory device for storing distributed voting logic based uponthe received signals and at least partially based upon parameter alarmsettings set within each monitor; and wherein at least one of themonitors is configured to control an operative state of a relay basedupon a combination of the distributed voting logic of the plurality ofmonitors; and wherein at least one of the monitors is configured toderive vibrational data from the received signals, and wherein thevoting logic thereof is at least partially based upon the vibrationaldata.
 28. The system of claim 27, wherein at least one of the alarmsettings is based upon a vibration level as defined by the vibrationaldata.
 29. The system of claim 27, the alarm settings are userconfigurable.
 30. A system for monitoring and protection a machine, thesystem comprising: a first sensor for detecting a dynamic operatingparameter of the machine at a first location of interest and forgenerating a first signal representative thereof; a first monitorcoupled to the first sensor for receiving and processing the firstsignal, the first monitor including a memory for storing voting logicbased upon the received signal; a second sensor for detecting a dynamicoperating parameter of the machine at a second location of interest andfor generating a second signal representative thereof; a second monitorcoupled to the second sensor and to the first monitor, the secondmonitor receiving and processing the second signal and including amemory for storing voting logic based upon the received signal, thesecond monitor being configured to control an operative state of a relaybased upon a combination of the voting logic of the first monitor andthe voting logic of the second monitor; wherein the first monitor isconfigured to provide an output signal to the second monitor based uponthe voting logic of the first monitor, and wherein the second monitor isconfigured to utilize the output signal of the first monitor in thevoting logic of the second monitor.
 31. The system of claim 30, whereinthe relay controlled by the second monitor is integrated into the secondmonitor.
 32. The system of claim 30, wherein the first and secondmonitors are configured to exchange data in accordance with an openindustrial data exchange protocol.
 33. A system for monitoring andprotection a machine, the system comprising: a first sensor fordetecting a dynamic operating parameter of the machine at a firstlocation of interest and for generating a first signal representativethereof; a first monitor coupled to the first sensor for receiving andprocessing the first signal, the first monitor including a memory forstoring voting logic based upon the received signal; a second sensor fordetecting a dynamic operating parameter of the machine at a secondlocation of interest and for generating a second signal representativethereof; a second monitor coupled to the second sensor and to the firstmonitor, the second monitor receiving and processing the second signaland including a memory for storing voting logic based upon the receivedsignal, the second monitor being configured to control an operativestate of a relay based upon a combination of the voting logic of thefirst monitor and the voting logic of the second monitor; wherein therelay controlled by the second monitor is integrated into the secondmonitor.
 34. The system of claim 33, wherein the relay controlled by thesecond monitor is incorporated into a relay module local to the secondmonitor.
 35. The system of claim 33, wherein the voting logic of thefirst and second monitors is at least partially based upon alarmsettings within the respective monitor.
 36. A system for monitoring andprotection a machine, the system comprising: a first sensor fordetecting a dynamic operating parameter of the machine at a firstlocation of interest and for generating a first signal representativethereof; a first monitor coupled to the first sensor for receiving andprocessing the first signal, the first monitor including a memory forstoring voting logic based upon the received signal; a second sensor fordetecting a dynamic operating parameter of the machine at a secondlocation of interest and for generating a second signal representativethereof; a second monitor coupled to the second sensor and to the firstmonitor, the second monitor receiving and processing the second signaland including a memory for storing voting logic based upon the receivedsignal, the second monitor being configured to control an operativestate of a relay based upon a combination of the voting logic of thefirst monitor and the voting logic of the second monitor; wherein thevoting logic of the first and second monitors is at least partiallybased upon alarm settings within the respective monitor.
 37. The systemof claim 36, wherein the alarm settings are user configurable.
 38. Thesystem of claim 36, wherein the first and second monitors are configuredto exchange data in accordance with an open industrial data exchangeprotocol.